MARLBORO, New Jersey — Tammy and Ted Plevretes don't need more research to link football concussions to devastating brain damage.

They need only look across the kitchen table, where their 23-year-old son Preston sits mostly silent in a wheelchair, a home-health aide at his side.

Four years ago, Preston took the field for La Salle University a month after an earlier concussion. He collided head-on with an opposing player on a punt return at Duquesne University on Nov. 5, 2005. He was briefly knocked unconscious, awoke and was combative for a few minutes, then lapsed into a coma.

He survived lifesaving surgery to remove a massive blood clot, and has since endured three more brain operations, a trip overseas for a stem-cell transplant and years of grueling therapy. Yet his progress has been limited, and he struggles to walk and talk.

This fall — amid rising awareness in the NFL about the long-term effects on the brain of repeated concussions — the Plevretes family settled a lawsuit against La Salle for $7.5 million. The suit charged that the Philadelphia school failed to treat Preston's first concussion properly, causing the later catastrophic injuries from what some doctors call "second-impact syndrome." La Salle argued the injuries stemmed solely from the hit at Duquesne.

"We still love football. We don't want anyone to stop playing it," said Tammy Plevretes, 49, of Marlboro, whose 60-year-old husband once played for the rough-and-tumble, semi-pro Brooklyn Mariners.

"(But) I think kids need to see what can happen," she said. "This isn't a broken leg. It's a broken life."

Preston was fortunate to be injured a few blocks from Mercy Hospital in Pittsburgh, where a pair of neurosurgeons on duty whisked him into an operating room. They removed a massive hematoma, stopped the bleeding and relieved the near-fatal pressure inside his skull.

Dr. Robert Cantu, a Boston-area neurosurgeon, served as the family's medical expert for the lawsuit. Cantu testified at this year's Congressional hearings on NFL concussions, telling lawmakers there is "growing and convincing evidence" repetitive concussions can cause degenerative brain disease.

Preston's erratic on-field behavior, combined with the excessive bleeding, point to second-impact syndrome, he said.

Once a person is vulnerable, additional brain trauma does not always have to be severe to cause devastating damage, Cantu said.

"The second blow may be remarkably minor, perhaps only involving a blow to the chest that jerks the athlete's head and indirectly imparts accelerative forces to the brain," Cantu wrote. Death can occur within minutes when the brain ruptures from the brain stem.

Such catastrophic injuries are rare. Cantu has treated about eight cases similar to Preston's, many of them youth football injuries.

The more common concern for NFL players — or anyone suffering multiple concussions — is dementia, depression and other neurological problems as they age.

"That's my biggest concern. How am I going to be when I'm 50 or when I'm 60? Will I have all these brain diseases and will I have a problem remembering things?" Brian Westbrook of the Philadelphia Eagles said after suffering two concussions in a three-week span this fall.

Westbrook, who missed seven games before returning to action Sunday, was not alone on the sidelines. Both of last season's Super Bowl quarterbacks, Ben Roethlisberger and Kurt Warner, and numerous other high-profile players sat out at least one game this season with concussions.

That's a stark turnaround from the days when such injuries often were ignored or hidden.

"Young athletes are horrible self-reporters. They want to please, they want to play, especially with a macho thing like football," said Brian Mason, who directs CentraState Wellness and Fitness in Freehold, N.J., where Preston spends much of his week in therapy.

The Plevretes, who refused to sign a confidential legal settlement, want youngsters to protect themselves.

"Be — safe," said Preston, mustering the focus and strength he needs to string together short, whispered phrases. "Do you — want — to end up — like me?"

In a sharp about-face this month, the NFL has encouraged players and their families to cooperate with Cantu and colleagues at the Boston University Center for the Study of Traumatic Encephalopathy, who are conducting autopsies on the brains of former athletes — and finding disturbing evidence of brain damage in football players, boxers and a former NHL player.

The NFL also has issued new concussion guidelines, and ordered independent physicians determine when a player should return. At youth levels, more teams are teaching players to recognize warning signs, including headaches, dizziness, tinnitus and blurred vision.

At least one neurosurgeon, Dr. Douglas Smith of the University of Pennsylvania, fears the new rules could backfire, leading players to try to hide their symptoms. Even doctors aren't sure when it's safe to return.

"That's the million-dollar question," said Smith, director of Penn's Center for Brain Injury and Repair. "If it were me, the appropriate time to go back is about 50 years."